The present invention relates to a mechanism for controlling the shutter speed of the electromagnetically driven shutter device with high accuracy.
So far there exsist several kinds of electromagnetically driven shutter devices. However, in all cases there take place the fluctuation of the load and so on due to the friction at the shafts of the shutter blades, the friction between the shutter blades (curtains) or the loose engagement between the mechanical members when the shutter is opened respectively closed. These load fluctuations often cause errors in the displacement speed of the shutter members, whereby especially when the shutter is at the same time made use of as diaphragm the actual operation often deviates largely from the desired optimal program diagram.
Namely, a proper exposure cannot be obtained, whereby especially the error of the high speed shutter operation is too large to realize the high speed exposure.